Excited states of donors in quantum wells in a magnetic field

Calculations of energy levels of a hydrogenic donor in the center of a quantum well show that, although the energy of the lowest-lying state of each symmetry tunes with the magnetic field much like its bulk counterpart, energies of the excited states in the well and in bulk have entirely dissimilar behaviors. Plots of energy versus magnetic field for these former states show a Landau-level fanlike structure starting near the lowest or first excited subband energy but interrupted by anticrossings with fans originating from alternating higher subbands. One interesting consequence is that certain states (the 2s and 2${\mathit{p}}_{+1\mathrm{}}$ levels, for example), which in bulk become widely separated in energy with increasing magnetic field, may remain close together over a wide range of fields in quantum wells.